|Publication number||US8235934 B2|
|Application number||US 12/527,765|
|Publication date||Aug 7, 2012|
|Filing date||Feb 20, 2008|
|Priority date||Feb 22, 2007|
|Also published as||EP2130492A1, US20100094223, WO2008102817A1|
|Publication number||12527765, 527765, PCT/2008/52886, PCT/JP/2008/052886, PCT/JP/2008/52886, PCT/JP/8/052886, PCT/JP/8/52886, PCT/JP2008/052886, PCT/JP2008/52886, PCT/JP2008052886, PCT/JP200852886, PCT/JP8/052886, PCT/JP8/52886, PCT/JP8052886, PCT/JP852886, US 8235934 B2, US 8235934B2, US-B2-8235934, US8235934 B2, US8235934B2|
|Inventors||Kazuyoshi Tsuchiya, Akifumi Morishima, Yasutomo Uetsuji, Takehiro Fukuzaki|
|Original Assignee||Tokai University Educational System|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (15), Referenced by (2), Classifications (13), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates to a functional thin tube device available for a case where body liquid such as blood is drawn, or where used as an analyzing needle, an injector of medical liquid, etc. in various fields such as a medical field or biological study field, or where the liquid is transported in a minute area.
2. Description of the Related Art
In general, a hollow tube as a channel path and a pump for energizing the liquid to flow in the tube are required for transportation of a small amount of liquid (movement, drawing, supply, carry, etc.) in the field of a medical care and a biological study. As the pump is an important component in the field of drawing small amounts of blood and in the field of medical equipment for the purpose of medical dosing, the important function such as the control of flow rate and volume of flow is required for the pump to transport the liquid through the hollow tube. In the field of the development of measuring devices of blood sugar level, which is, in particular, popular in the field of medical care, it is important for the pump to be able to deal with a small amount of liquid such as blood.
In a conventional blood sugar level measuring device for testing diabetes, approximately 10 ml of blood of outpatients is drawn by an injector based on the pharmaceutical affairs law, and the blood sugar level thereof is measured by a well-known blood-analysis system using a flow injection method having a centrifuge and a pump function. At present, simplification, compactization, and invasions to the human body are required. Therefore, disposal sensors for self-testing of blood sugar level have been developed to be able to measure the blood sugar level at an extremely small amount like being less than or equal to 1μ liters, and are commercially available for a portable blood analysis system.
The above-mentioned disposal sensor for management of self-blood sugar level is required (1) for injection movement for piercing the injection measurement device such as a lancet in a finger or abdomen, and (2) for sophisticated manual operation for sucking the about 1μ liters blood as exuded at a lancer spot by a tester himself. This can be undesirable for patients. The outside diameter of a needle for the lancet necessitates hundreds of μ meters. Then, the influence to the human body owing to the drawing blood, in particular, significant discomfort, can result. Though the micro pump for drawing blood using an extremely thin needle so as to reduce pain and discomfort has been developed and studied, in some cases devices are required to be more compact than such needles for the pump function. On the other hand, the micro machine technique (MEMS: micro electro mechanical systems) of manufacturing devices such as a micro machine device provide opportunities to develop the transportation of a small amount of liquid chemical and a drawing small amounts of blood.
For example, the following technique has been known as the above-mentioned method for manufacturing such a micro machine device. This technique includes, at first as “Lab on a chip”, a small flow path on a glass plate or high polymer base plate to seal by an adhesion of an elastic body such as rubber. Further, the functional material for obtaining the force by transforming the electrical energy into the mechanical energy is placed on the elastic body. The flow function is applied to the device itself by applying forces from the top of liquid sealing rubber thereto. For example, this kind of technique has been disclosed, for example, in Japanese Patent Unexamined Laid-Open Publication No. Heisei 5-26170.
However, as the above conventional micro machine device is required for a sophisticated channel design, it is difficult to design or process the device into a shape other than a plate-like shape. As in a conventional blood sugar level measuring device, the development of both a pump and a blood (liquid) drawing device is required. Since the channel design is formed on a base plate, it has some significant limitations in how and where it can be used.
The present invention is considered in view of the present situation as above mentioned. The present invention is constituted to be simple, without requiring a sophisticated channel design by integrating a pump and a channel. Thus, an object of the present invention is to provide a functional thin tube device that can be used in various applications.
The inventors have analyzed a movement of body structure of an earthworm and tried to apply it to a structure of the functional thin tube device, when they thought that the pump function was integrally constituted in a thin tube for enabling the fluid to move. That is, as an earthworm has a two-layer muscle composed of a longitudinal muscle along a longitudinal direction of the body and a ring-shaped muscle along a circumferential direction thereof. The behavior of peristaltic movement in earthworms has been known to be made by the contraction of muscles and the change of length and width of the body. When a constitution for performing the same movement as the above peristaltic movement was obtained by vibrations, the inventors considered that it would be possible to provide a micro device and to design a device having both a pump function and transportation function.
In the present invention, the inventors paid attention to the fact that the peristaltic movement, which is like a way of movement of human intestines or an earthworm, is essentially a progressive wave. In an ultrasonic wave motor, as an example of a progressive wave which is put in practice and commerce, an ellipsoidal movement occurs on any point of the surface of vibrating body by the progressive wave caused by the vibration of a piezoelectric material. Then, it has been already known that a rotating movement occurs by shifting a moving body (rotor) from the initial position due to the friction cased by the ellipsoidal movement of the vibrating body. It has also been known that a frictional force prevails against gravity or inertia in a microscopic area like an extremely thin tube as the liquid flowed, in a case where the above phenomenon is applied to the fluid.
Accordingly, the progressive wave, which occurs on a surface of an extremely thin tube by an addition of dynamic vibration transmitting from the ring-shape vibrating ring body forming a film in the extremely thin tube, transmits vibrations from an inner wall of the extremely thin tube to the liquid and the friction occurs between the liquid and the inner wall of the extremely thin tube. The present invention has been made after the verification of a mechanism to flow the liquid in the tube according to the frictional function caused by the vibration as transmitted to the liquid.
In one embodiment, a functional thin tube device relating to the present invention includes a hollow tubular body, a plurality of vibrating ring bodies in contact with the tubular body spaced an appropriate interval along an axial direction on an outer circumference of the tubular body, and an energy supply means for vibrating the vibrating ring body. The energy supply means is configured to supply energy such that amounts of displacement caused by vibrations are mutually different among the vibrating ring bodies.
The above functional thin tube device is constituted to have different amounts of displacement of the vibrating ring bodies. For example, when different vibrations caused by the vibrating ring body placed at an even position or at an odd position occur, the progressive waves are created and are different in size in the liquid inside the tubular body. Thus, this synthesis of progressive waves results in an occurrence of the progressive wave, having an ellipsoidal orbit, in the liquid inside the tubular body. The progressive wave having the ellipsoidal orbit makes the liquid in the tubular body more in a transporting direction. In addition, the functional thin tube device can be used as a means for connecting various equipment such as an injector, by arranging a tip thereof to be at a right angle.
Accordingly, the functional thin tube device can be made smaller in size, as the vibrating ring body equivalent to a pump section and a tubular body equivalent to a portion for transporting the liquid are integrally formed. Thus, the functional thin tube device is available in a microscopic portion. The functional thin tube device can control the volume of flowing or the flow rate of the liquid as transported by the displacement of the vibrating ring body and the timing of vibration.
In the above mentioned functional thin tube device, the vibrating ring body can include a piezoelectric element formed like a ring shape, and a metal electrode provided on an inner surface and on an outer surface of the piezoelectric element. Further, the energy supply means may be, for example, a voltage supply means applying the voltage to the piezoelectric element.
In such a constitution, the functional thin tube device can also provide a device having a tubular body as formed to be smaller in diameter by the spattering pile method.
In addition, the tubular body may be made of metal and formed to be an edge surface of an injector, of which the top end has a sharp angle. Accordingly, the functional thin tube device can be made to be smaller and miniaturized in size so as to reduce pain and discomfort when human skin is pierced with an injector.
The tubular body may be made of flexible material like rubber or plastics, thus to be able to extend an available area thereof.
The vibrating ring body may be configured to form a groove portion or a notch portion along an axial direction of the tubular body.
In such a functional thin tube device, the groove portion or the notch portion makes the width of vibration of the vibrating ring body to be larger in amplitude as compared with a ring-shape state. Then, the functional thin tube device can extend an area of dynamic range, in which the flow rate can be preferably controlled at the time of the transportation of liquid in the tubular body.
Further, in the functional thin tube device, the voltage supply means may be constituted to apply with a gradient of voltage in order to lower the voltage as applied toward a transportation direction of liquid transporting in the tubular body.
In such a functional thin tube device, it is easy to transport the liquid flowing in the tubular body toward the transportation direction, and also to transport the highly viscous liquid. In addition, the voltage supply means is configured to provide a gradient of voltage by directly changing the voltage, and to provide a gradient of voltage with the resistance arranged in a line between the voltage supply means and the piezoelectric element.
The energy supply means can be configured to supply energy such that the vibration of the vibrating ring body placed at an even position or at an odd position becomes a sympathetic frequency of the tubular body.
In such a configuration, the functional thin tube device can raise an efficiency of transportation of the liquid by the progressive wave having an ellipsoidal orbit to make larger vibration relative to the tubular body.
The energy supply means can be configured to supply energy such that the displacement occurring in either one of the vibrating ring body placed at an even position or at an odd position is larger.
In such a configuration, the vibrating ring body supplies the vibration to the tubular body. Then, it is easier to transport the liquid inside the tubular body by the help of the progressive wave.
Hereinafter, an embodiment for carrying out the present invention will be described in detail with reference to drawings.
As shown in
The tubular body 2 can be a thin tube made of metal as one example in this embodiment. The tubular body 2 is formed by a material having an adaptable property for human body such as titanium or titanium alloy. The tubular body 2 may be formed as an edge surface 5 of an injector by means of a laser cutting in an oblique direction of one end thereof, if necessary. The tubular body 2 can be configured to transmit applied vibration to the inside of the tube, and may be made of flexible material like rubber or plastic. A diameter of the tubular body 2 can, for example be in a range from hundreds to decades of μm. For uses such as drawing blood piercing human skin or medicine dosing, a range from 500 to 50 μm can be used in order to relieve a psychological burden feeling pain. The fabrication of such a thin tube can be manufactured by drawing, in a case where the tubular body 2 is metallic thin tube. In a case where the thin tube is smaller in diameter, it can be manufactured by, for example, a spattering pile method. For example, it may be referred to Japanese Patent Unexamined Laid-Open Publication No. 2004-232077.
A plurality of vibrating ring bodies 3 are arranged to space a constant interval, and have a piezoelectric element 3 a formed like a ring shape and metal electrodes 3 b, 3 c provided in an inner and outer surface. The vibrating ring body 3 is integrally formed to be in a block and a surface of the inner circumference thereof is in contact with the tubular body 2. The vibrating ring body 3 may be integrally formed by the spattering pile method to be in a block together with the tubular body 2, in a case where the diameter thereof is less than or equal to 500 μm (decades of μm). For example, in a case where the tubular body 2 is beyond 1 mm in diameter and 5 cm in axial length, the vibrating ring body 3 and the tubular body 2 may be separately manufactured to form in a block by adhesives or by thermal procedures. In addition, it is preferable to have an even the number of the vibrating ring bodies 3.
The piezoelectric element 3 a can be, for example, PZT (lead zirconate titanate) element, and can be a solid solution of Perovskite type PbZrO2 and PbTiO3 to show a property of ferroelectrics. The piezoelectric element 3 a and metal electrodes 3 b, 3 c are integrally arranged in a block to the tubular body 2, for example, by spattering, depending on the size thereof.
The metal electrodes 3 b, 3 c are, for example, made of metallic thin film such as platinum, gold, or silver thin film. The metal electrodes 3 b, 3 c may be an alloy or the other conductive material to be able to apply the voltage to the piezoelectric element 3 a.
In this embodiment, the voltage supply means 4 is used as an energy supply means. The voltage supply means 4 is designed to apply the energy to vibrate the piezoelectric element 3 a. The voltage supply means 4 can be provided with two voltage sections 4 a, 4 b applying the voltage in order to generate different vibrations, depending upon whether the piezoelectric element 3 a is placed at an even position or an odd position. The voltage supply means 4 is, for example, constituted such that the piezoelectric element 3 a placed at an even position and the piezoelectric element 3 a placed at an odd position are mutually different in amplitude of voltage, and a waveform of voltage is different depending upon the frequency. This voltage has, for example, a relationship shown in the following expressions (1) and (2).
V 1 =A ch1 sin 2πf ch1 t (1)
V 2 =A ch2 sin 2πf ch2 t (2)
Where Ach1 and Ach2 are amplitudes based on output voltage, fch1 and fch2 are applied frequencies, t is a time, the number of ch1 and ch2 correspond to numbers of applied alternative current,
V1 is the voltage of the piezoelectric element placed at an odd number, and
V2 is the voltage of the piezoelectric element placed at an even number.
The frequency in expression (1) and (2) is preferable in order to satisfy a condition of the following expression (3).
f ch2 =nf ch1 or 1/nf ch1 (3)
The ‘n’ in expression (3) is an integer except zero.
As shown in expression (3), the vibration changes according to either an even position or an odd position of the piezoelectric element 3 a such that the progressive wave is generated in the tubular body 2. The liquid is transmitted from one side to the other side according to the generated progressive wave. In the relationship between f ch1 and f ch2, it is preferable that one frequency is equal to a multiple of the other frequency, or that one frequency is equal to an inverse number of a multiple of the other frequency.
Though both of the above piezoelectric elements 3 a receive data composed of sine curve waves, the data may be shifted in phase to become a relationship between a sine curve wave as one data and a cosine curve wave as the other data, and applied to the piezoelectric element 3 a in a different wave cycle.
As shown in
A portion surrounding the tubular body 2 and the vibrating ring body 3 is covered by a cover 7, which is, for example, a rectangular prism or a cylindrical prism made of plastic material with one end and the other end of the tubular body to be exposed. The voltage supply means 4 and the portion of the tubular body 2 and the vibrating ring body 3 are configured to be connected by an electric code 6 a, thus to be kept apart. The voltage supply means 4 is provided in a box-shape power source 6 to actuate as a control section. The box-shape power source 6 is provided with a display 6 b, a power source switch 6 c, and a control tab 6 d, 6 d, etc.
An example of a method for manufacturing the functional thin tube device will be described with reference to
In this example, a portion of the thin tube of the functional thin tube device 1 is formed by a spattering pile method. The spattering pile method is a method for making a film such that rare gas such as Argon introduced in vacuum is ionized, the ionized particles collide with a target, and the particles reflected on the target reach a base plate (a core material). As a concrete example, the covered film made of titanium on a surface of core material W made of copper is formed by the spattering pile method. The tubular body 2 is made to dissolve and eliminate the core material W made of copper at a manufacturing step or a final step by an etching liquid such as an acid. Silver (gold, platinum) thin film is formed as the metal electrode 3 b, 3 c in the tubular body 2. Then, the thin tube is constituted to form silver (gold, platinum) thin film as the metal electrodes 3 b, 3 c in the tubular body 2 and to form the PZT element in a ring shape as the piezoelectric element 3 a. The manufacturing step of the functional thin tube device 1 will be described in the following.
As shown in
After a film of the target material T is formed on the core material W, the film formed in the vacuum or in Argon atmosphere (preferably 10−5 Pa) is thermally processed at a re-crystallized temperature thereof in a vacuum furnace to avoid a hydrogen embrittlement. The thermal procedure enables the film to re-crystallize. In addition, by arranging a heater in the vacuum receptacle 11 (for example, installing in a rectangular portion grasping the core material W) the film material can be thermally processed through the core material W, and also thermally processed in the atmosphere of air with an electric furnace, depending upon the film material. After the thermal procedure, the tubular body is taken out from the vacuum receptacle 11.
Next, as shown in
When forming the vibrating ring body 3, an inorganic acid such as nitric acid, which is a corrosive medium, etches the core material W to eliminate the core material W from the tubular body 2. In addition, the timing for etching the core material W may be after forming the tubular body 2.
The tubular body 2 and the vibrating ring body 3 form a connecting portion 3 d or a connecting circuit for connecting the metal electrode 3 b, 3 c to the electric power source in the prescribed position of the tubular body 2. In the alternative, an ink-jet printer etc., can be used to form the connecting circuit by laser sintering, and to connect the electric cable (code 6 a) from the outside at one end thereof. In addition, the inside metal electrode 3 b may form the connecting portion by remaining wider in width than the width of the piezoelectric element 3 a.
In the functional thin tube device 1 as manufactured, the tubular body 2 can be, for example, less than or equal to 500 μm in diameter and more than or equal to 5 μm in thickness. In this example, the tubular body 2 is formed to be 50 μm in diameter (outer diameter) and 12.5 μm in thickness. In addition, the length of the tubular body 2 can be formed in a range from several millimeters to several centimeters, depending upon a size of the vacuum receptacle 11. The size of 50 μm in diameter is the approximately same size as the mouth of the female mosquito. In a case where the functional thin tube device 1 is 50 μm in diameter, the injector can pierce human skin without pain to a human body, in order not to form an edge surface of the injector at one end of the tubular body 2.
After the tubular body 2 is formed by the spattering pile method, a method for making a pipe where the core material W etched, is a so-called bottom-up manufacturing method, which dissolves only a substrate material by a corrosive liquid after forming a film on a surface of the wire-shape substrate material as a target material such as thin tube material is rotated. Thus, the extremely thin tube having an appropriate inner and outer diameter, and having an appropriate shape can be manufactured.
Next, an operation of the functional thin tube device 1, will be described, with reference to
As shown in
In the piezoelectric element 3 a, an alternative voltage having a phase difference such as a sine wave at an odd position and a cosine wave at an even position is applied thereto, and the two alternative voltages different from the frequency is applied. The generation of the progressive wave M and m caused by the alternative voltage E1 and E2 generates a synthetic progressive wave generating a synthetic wave, that is, an ellipsoidal movement resulted from the two progressive waves M, m. Then, as shown in
As shown in
As shown in
In the tubular body 2, the synthetic progressive wave D having the ellipsoidal orbit as synthesized is generated by the vibration of the vibrating ring body 3 to vibrate the liquid in the tubular body 2. The synthetic progressive wave D is a progressive wave having an ellipsoidal orbit e to generate an ellipsoidal movement at an appropriate point of an inner surface of the tubular body 2 as vibrated by the vibrating ring body 3, as shown in
As a condition for generating the synthetic progressive wave D having an ellipsoidal orbit, a fluctuation of the displacement of the vibrating ring body 3 is controlled by changing the applied voltage and frequency (for example, referred to the above-mentioned expression 1 and 2). In a case where the sympathetic frequency of the tubular body 2 is applied to the vibrating ring body 3 placed at an odd position according to the present invention, the frequency other than the sympathetic frequency is applied to the vibrating ring body 3 placed at an even position. This means that the vibrating ring body 3 placed at an odd position generates a maximal displacement and the vibrating ring body 3 placed at an even position generates a smaller displacement than the maximal displacement. This applies in a case where an inverse frequency is applied to the vibrating ring bodies 3 placed at an odd position or at an even position.
The other condition for generating the synthetic progressive wave D having an ellipsoidal orbit e is a timing control superposing the wave. This is caused by the displacement of two vibrating ring body 3 so that the synthetic progressive wave D (thick line in
The disposition of even numbers of the vibrating ring body 3 can make faster a flow of the synthetic progressive wave D. The amount of the applied voltage slants toward a direction for transporting the fluid to cancel a restrictive condition in which a number of the vibrating ring bodies 3 must be an even number. Then, the loss caused by the offset among the synthetic progressive waves D can be decreased. Thus, the improvement of pump performance of the functional thin tube device will be expected.
Preferably, the voltage applied to the piezoelectric element 3 a decreases from upstream to downstream in the advancing direction. The progressive waves are controlled by a voltage gradient such that one wave does not influence other waves among the progressive waves, so as not to cancel each other. As a result, the high flow speed of the wave can be obtained. In this case, the number of the piezoelectric elements 3 a is not required to be an even number. Further, instead of the voltage gradient, for example, the resistance arranged between the piezoelectric element 3 a and the power source can result in a gradient in an amplitude of wave of the progressive wave M in the tubular body 2 because of the decrease of the amplitude of wave to have the same effect as the above.
In addition, the explanation in the tubular body 2 of the above-mentioned functional thin tube device 1 is similar to a principle of an ultrasonic motor in view of a use of the synthetic progressive wave D having an ellipsoidal orbit e. However, although an ultrasonic motor excites the progressive wave in a vibrating body and is used as a frictional actuation with a frictional material, embodiments of the present invention are designed to transport the fluid by generating the synthetic progressive wave D, having the ellipsoidal orbit e, directly in the fluid inside the tube. In addition, the present invention is adopts a principle of emitting the wave on the wall which the reflecting coefficient is less than 1, and to generate the progressive wave depicting an ellipsoidal orbit by the synthetic wave together with the reflected wave as generated in this occasion.
As above described, the functional thin tube device 1 generates the synthetic progressive wave D without using a check valve to become a micro pump for enabling the fluid inside the tubular body to transport.
A form of the vibrating ring body 3 may be a for example, as shown in
In the following, an example using a silicon tube, which is large in diameter, will be explained to ascertain the function of the functional thin tube device according to an embodiment the present invention. The present invention is not limited to this example.
As shown in
In addition, the ring-shaped PZT element 33 and a silicon tube 32 are adhered, for example, by a CEMEDINE (Registered Trademark), which is a commercially available adhesive. The silver electrode (not shown) is applied on an outer surface and an inner surface of the ring-shape PZT element 33. The ring-shaped PZT element 33 is driven and vibrated by applying the alternative voltage from the voltage supply means 34. This vibration causes the progressive wave to generate in the fluid inside the silicon tube and generates an ellipsoidal movement at an appropriate point of the fluid. Then, the fluid inside the tube is transported in accordance with the deviation from the initial point because of the viscosity of the fluid. A situation generating the progressive wave can be changed by the influence of an element of the voltage and the frequency applied to the ring-shaped PZT element 33. Then, a condition for enabling the velocity of the fluid inside the tube to control is carefully considered. An applied waveform is taken as a sine wave and a cosine wave in the direction of polarization directing to the diametrical direction from a center of the silicon tube.
The displacement of the ring-shape PZT element effects the transportation of the fluid inside the tube. The product C-9, made by FUJI Ceramics Co. Ltd. is used as the ring-shaped PZT element in this example. The piezoelectric constant d33 of PZT as used in this example is 718 μm/V. As the displacement of ring-shaped PZT element 33 is extremely small, the displacement in a state attaching the silicon tube 32 is measured by a laser doppler vibrator. A voltage of 60 Vp-p is applied to the ring-shaped PZT element to change the frequency. The effect, as above obtained, is shown in
In the liquid transportation by vibration in tubular body, the more amounts of vibration and displacement, the more amounts of the liquid transportation. Although it has been known to be a large amount of vibration or displacement in a plate-like bimorph type or a multi-layer type, a preferable form is unknown in case of a ring shape. The mono-morph type ring-shaped PZT element 33 is used as the micro pump 31 in this example. This is based on the two-layer type being designed to pile the PZT element, which is the same direction as the polarized direction and a size larger, is estimated to be insufficient as the multi-layer type.
As shown in
In this flow functional experiment, the positive voltage is applied to the PZT element as shown in
In a use of the experimental device 20 as shown in
Further, two patterns of 60 Vp-p (offset voltage: −30V) and 80 Vp-p (offset voltage: −40V) are applied. The result of a fluidized functional experiment by the above method is shown in
When the frequency outputting from the ch2 is more than or equal to 3.0 kHz in this example, there was no difference in the change of flow rate in case of the applied voltage 60 Vp-p and the applied voltage 80 Vp-p. Though it is considered to be a decline of the displacement caused by shifting from the sympathetic frequency of the ring-shaped PZT element 33, the fact that it is not able to follow the fluid inside the tube may be considered as the other cause. Though water is applied as an estimating fluid in this example, an application for medical field will be expected. That is, considering the blood having high viscosity, an increase of the friction force in the inner surface of the silicon tube and a followability in the range of the fluid having high-frequency band can be expected, as the blood has a higher degree of viscosity than water.
As a comparison, a change of the flow rate is also verified, in a case where the offset waveform and normal wave are applied to a plus side. At first, the experimental effect is shown in
However, the principal point, which is different from the case as an offset waveform as applied to a minus side, enables the decrease of flow rate to be realized by increasing the applied voltage. In this case, the ring-shaped PZT element is limited to the displacement extending the ring-shaped PZT element in a diametrical direction. Thus, as it is considered that a frictional actuation between an inner wall of the silicon tube 32 and the fluid has not occurred, a decrease of the efficiency may be caused by this reason. In this case, it is considered not to be influenced by the frictional actuation on a surface of the silicon tube 32, but by the occurrence of negative pressure in the small displacement of the ring-shaped PZT element. The search in an appropriate condition is considered to improve or increase an efficiency of the decrease of the flow rate owing to the applied voltage. Then, it has proved that the offset waveform applied to a plus side is effective in the decrease of the flow rate inside the tube.
In this example, the decrease of flow rate can be ascertained at a comparatively low situation of the output frequency from ch2, as well as the case of the offset in a minus side. Thus, it has resulted in that the increase rate of the flow rate is inferior to the offset waveform in a minus side, but the decrease rate of the flow rate is superior thereto.
As above mentioned, the functional thin tube device can be smaller and more microscopic in size, as the pipeline composed of tubular bodies and the pump section composing of the vibrating ring body are integrated. Thus, the functional thin tube device can be available for a wide range of uses, for example from a field of MEMS to a medical field such as medicine dosing and drawing blood.
Except the fluidized function, an extremely thin tube itself can behave like a movement similar to a peristaltic movement of an earthworm. If an extremely thin tube having a multi-functional property can be manufactured, the application to a medical field such as an artificial blood vessel can be expected. On manufacturing the thin tube for use in the technique for manufacturing an extremely thin tube, it can be used as a pipeline of the liquid such as blood and liquid chemical. The development of a device, which is operable in an extremely microscopic field such as an area inside human body including blood vessels as being normally inoperable for a man, can be expected.
Though the voltage supply means as one example of an energy supply means and the piezoelectric element as a vibrating ring body have been explained in this description, the means for transforming the energy to a mechanical vibrating energy may be used, for example, titanium dioxide vibrating by means of a supply of photo energy from the energy supply means, or shape memory alloy vibrating by means of a supply of thermal energy from the energy supply means may be used.
As the functional thin tube device is configured to integrate the vibrating ring body having a pump section and the piping forming a portion of the liquid transportation, it is easy to be small in size. Then, it can be used in a small portion (section).
As the functional thin tube device is designed to control the volume of flow or the flow rate of the liquid as transported by displacement, vibrations and a timing control of the vibration of the vibrating ring body, a high quality of micro pumps can be developed.
The functional thin tube device is formed, for example, by a metal to be an edge surface of the injector needle by machining one end thereof, thus to integrate a portion of an injector needle, a pump section, and a tubular body in a block. Then, as the device becomes compact, it is able to have a lower level of invasiveness during injection in the skin of humans and animals, and to relieve the discomfort and burden of patients accompanying with a movement for piercing with an injector.
The functional thin tube device can be extended to a wide range of use thereof by manufacturing the tubular body made of flexible material such as silicon rubber.
The functional thin tube device can make vibration relative to the tubular body to be larger by forming a groove portion and a notch portion in the vibrating ring body. Accordingly, a wide dynamic range to control the flow rate can be obtained in transporting the liquid in the tube body.
The functional thin tube device can make the vibration of the progressive wave for transporting the liquid inside the tube to be larger by corresponding the vibration of the vibrating ring body to the sympathetic frequency of the tube body.
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|US9068566 *||Jan 20, 2012||Jun 30, 2015||Biodot, Inc.||Piezoelectric dispenser with a longitudinal transducer and replaceable capillary tube|
|US20120304929 *||Jan 20, 2012||Dec 6, 2012||Biodot, Inc.||Piezoelectric dispenser with a longitudinal transducer and replaceable capillary tube|
|U.S. Classification||604/22, 422/549|
|Cooperative Classification||A61B5/1411, F04F7/00, F04B19/006, F04B43/095, F04D33/00|
|European Classification||A61B5/14B2, F04B19/00M, F04D33/00, F04F7/00, F04B43/09P|
|Sep 11, 2009||AS||Assignment|
Owner name: TOKAI UNIVERSITY EDUCATIONAL SYSTEM,JAPAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TSUCHIYA, KAZUYOSHI;MORISHIMA, AKIFUMI;UETSUJI, YASUTOMO;AND OTHERS;SIGNING DATES FROM 20090801 TO 20090831;REEL/FRAME:023223/0755
Owner name: TOKAI UNIVERSITY EDUCATIONAL SYSTEM, JAPAN
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:TSUCHIYA, KAZUYOSHI;MORISHIMA, AKIFUMI;UETSUJI, YASUTOMO;AND OTHERS;SIGNING DATES FROM 20090801 TO 20090831;REEL/FRAME:023223/0755